$re = '/<input\s+name="data\[Product\]\[name\]"\s+value="([^"]+)"/';
$str = '<input name="data[Product][name]" value="Бумага SvetoCopy Ð4 80г/м 500л." type="hidden">
<input name="data[Product][name]" value="Бумага SvetoCopy Ð3 80г/м 500л." type="hidden">
<input name="data[Product][name]" value="Бумага Снегурочка Ð4 80г/м 500л." type="hidden">
<input name="data[Product][name]" value="Ручка гел. Ñин 05 ЕК8791" type="hidden">';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php